Helicopters and other vertical take-off and landing aircraft essentially require a horizontal and flat landing space. Inclined or irregular surfaces are unsuited for landing such craft because of the dangers associated with other than horizontal rotation of the craft's rotors. Thus, for safety of the aircraft and any persons on the ground, the landing gear of all such aircraft form a horizontal plane for landing on a flat landing pad or relatively flat ground.
For many thousands of years, mankind has dreamed of being able to fly as he has watched the beauty and technological wonder of birds in flight. Since the days of Kitty Hawk and the Wright brothers, the airplane has given man the ability to take flight. An airplane, however, cannot match the ability of birds to take flight from almost any location and to land in almost any location. The airplane requires the long hard surface of a runway to get enough speed to create lift or to safely return to earth. The invention of the helicopter has so far been the closest to the technological ability of a bird to take off and land in any desired location.